The environmental movement in the United States and abroad continues to grow into a mainstream concern with growing demand for environmentally friendlier (“green”) products and programs to remove hazardous materials from the residential and workplace environment. PVC (polyvinylchloride) and formaldehyde-based laminate worksurfaces and components are now being removed from many applications due to their toxic nature. Many businesses and organizations are taking aggressive action to remove PVC and formaldehyde-based products from the interior workplace and product fines.
The demand continues to grow for “green” products to replace petrochemical plastics and hazardous polymer. This demand is driven by environmental awareness and by the architectural and building communities based on making interior environments healthier. Materials commonly used in many architectural, institutional, and commercial applications for vertical and horizontal surfacing products are primarily derived from PVC and melamine formaldehyde laminates. With growing concerns over the usage of hazardous PVC and formaldehyde in interior applications, there is a need for environmentally friendly alternatives that meet both performance and economic requirements.
Formaldehyde has created serious concerns over interior air quality. Products such as particleboard and high pressure laminates use substantial amounts of formaldehyde in their resinous makeup. In many cases, the formaldehyde is not removed completely from the product and is introduced into interior public or residential closed spaces and may off-gas for an extended time. Formaldehyde has been linked to many health problems and is classified as a known carcinogen. Major corporations have now made public policy statements that they are to remove PVC and formaldehyde from their places of work. Japan has put in legislation creating strict policies inhibiting the usage of PVC and formaldehyde containing products. Similar legislation has been enacted in Europe.
PVC has been classified by many groups as a “poison plastic”. Over 7 billion pounds of PVC is discarded every year. The production of PVC requires the manufacturing of raw chemicals, including highly polluting chlorine, and cancer-causing vinyl chloride monomer. Communities surrounding PVC chemical facilities suffer from serious toxic chemical pollution of their ground water supply, surface water and air. PVC also requires a large amount of toxic additives resulting in elevated human exposure to phthalates, lead, cadmium tin and other toxic chemicals. PVC in interior applications releases these toxic substances as volatile organic compounds (VOCs) in buildings. Deadly dioxins and hydrochloric acids are released when PVC burns or is incinerated.
The vast majority of vertical or horizontal decorative surfacing materials are high pressure laminates and thermofoil PVC. Work surfaces, tables, desktops, and many other work surfaces glue a thin high pressure laminate (HPL) (typically 0.050 inch thickness to a wood particleboard adhered with urea formaldehyde glues). Over the last decade, many kitchen cabinets were produced by cutting a medium density fiberboard containing phenol formaldehyde glues into a door shape. A thin PVC sheet or thermofoil was heated and pressed onto this three dimensional shaped door using a membrane press. The resultant door was already finished and resistant to water, but contained high amounts of chlorine. If the cabinets were burned, the off-gassing may create a deadly hydrochloric acid gas for fire fighters or people who may not escape the fire.
Biobased material is seen as an ideal solution in the architectural, institutional, commercial and even residential markets. Despite this, few products have entered the market as a direct replacement for PVC thermofoils used in surfacing and formaldehyde-based laminates. Biorenewable materials are preferred over petrochemically derived plastic products. Bioplastics have been commonly used for various packaging film applications. Primarily PLA (polylactic acid) has been the most commercially successful of these bioplastics. PLA is a hard brittle plastic that is highly mobile or quickly turns into a liquid under open flame conditions. In addition, PLA may not be easily extruded into profile shapes due to its high melt index and unique rheology. Most all of current PLA products are based on creating biodegradability. As one can appreciate, however, it is not always desirable that products in long term commercial applications be biodegradable, even where biorenewability is desired.
“Green” products have long been desired and are coming into the mainstream, but in most cases biomaterials or “green” solutions have come at a high price and typically do not meet the required performance standards. In some cases, people or companies will pay slightly more for a “green” product, but in reality, a “green” product needs to meet performance while being competitive in price. Being “green” is important, but the ability to supply performance at a competitive price is important to commercialization of “green” technologies. It is important that the materials and products within this environment are not harmful to overall health and provide a clean, VOC-free environment. PVC and its additives, along with formaldehyde from laminates and some particleboards, release harmful VOCs into the work place. These VOCs have been classified as potential carcinogens, creating a higher risk of cancer.
Although “green” biodegradable packing materials are moving the global community towards better environment practices, there exists a strong market demand for non-biodegradable biorenewable materials for more permanent applications to replace hazardous or petrochemically-derived products.
Methods known in the art for making final laminates include Low Pressure Laminate (LPL), High Pressure Laminate (HPL) and Continuous Pressure Laminate (CPL) processes. Low pressure is most often used with card-board or particle board, whereas high pressure generally is used with the so-called kraft papers. The sheets or products resulting from the HPL process are generally not self-supportive. They are often bonded, with a suitable adhesive or glue, to a rigid substrate such as particle board or medium density fiber board (MDF). In a continuous pressure laminate process, papers may be fed from a role into a continuous belt press.
Traditional production suffers from drawbacks which are not easily overcome. One problem is that the laminates made in the high pressures or continuous process are so hard, that it is difficult to bend or ‘post-form’ these sheets. At present, post-forming characteristics are often achieved by either incorporating expensive modifiers like benzoguanamine or acetoguanamine, or by making melamine-formaldehyde resins at elevated pressure, allowing more melamine to react with formaldehyde. The latter process is relatively expensive, and requires pressure vessels. Yet, it may be advantageous if, while keeping the abrasion resistance and chemical resistance properties, the HPL or CPL sheets would be bendable, so they could be made to cover a substrate not only on one side, but in one process step. Another drawback of traditional laminates is the use of formaldehyde, which is known to be a toxic chemical. The resin used to impregnate traditional paper may be a formaldehyde-melamine resin. After curing, the laminate may still release some formaldehyde, which may cause environmental concerns.